Valve for the projection of digits and characters for counters and computers



March 19,- 1963 P. BALASKOVIC 3,082,341

VALVE FOR THE PROJECTION OF DIGITS AND CHARACTERS FOR COUNTERS AND COMPUTERS Filed Feb. 10, 1959 AGENT VALVE FOR THE PRUJECTEGN F DIGHS AND CHARACTERS FGR COUNTERS AND CUM- PUTIERS Pierre Ealashovic, La ilourneuve, France, assignor to North American Philips (Zompany, Inc, New York, N.Y., a corporation of Delaware Filed Feb. 19, 1959, Ser. No. 792,427 Claims priority, application France Feb. 12, 1958 Claims. (Cl. 313-70) This invention relates to character display devices which reproduce the presence of one or more given voltages from a limited number of voltages by means of a luminous signal. The luminous signal may be, for example, a character or a digit. The total of the voltages may be a complex which is characteristic of the condition of an electrical device with multiple positions, for example a counter.

The invention relates more particularly to tubes of the kind containing in a common envelope a cathode for pro ducing a primary beam of electrons, a fluorescent screen, means provided between the cathode and said screen for producing a plurality of beams each having cross-sections corresponding to the characters, and focussing means for concentrating said latter beams onto the fluorescent screen.

An object of the invention is to design such tubes so as to satisfy better than hitherto the different requirements of practice and more particularly to reduce their consumption or" energy and the control voltages required.

The invention especially relates to the use, in such a tube, of means arranged at right angles to the primary beam of electrons for producing the plurality of beams, which means comprise the combination of a conductive anode provided with apertures corresponding to the signs to be reproduced and a control member consisting of a plurality of grids, each grid in accordance with the invention being positioned such that, by means of the potential applied thereto, it can control the electron current passing through a given part of the perforated surface of the anode.

A valve according to the invention, intended more particularly for indicating the presence of a given voltage from a limited number of voltages, may more particularly have the characteristic that a suitably shaped aperture of the anode corresponds to each character to be reproduced and that the electron current passing through this aperture is controlled by the potential applied to the grid associated with the relevant aperture, the said focussing means comprising a magnifying electron-optical system which concentrates the beams 'of secondary electrons onto the same part of the fluorescent screen.

The invention will now be described, with reference to the accompanying drawing, in which:

FIG. 1 shows diagrammatically a tube according to the invention;

FIG. 2 shows diagrammatically a variant of the embodiment of FIG. 1;

FIG. 3 is an elevational view of the apertures in an anode of a tube according to the invention, and

FIG. 4 shows two examples of the signs obtained with the anode shown in FIG. 3.

The envelope of the valve, which is not shown in FIG. 1, surrounds the complex of the above-mentioned electrodes and partly merges into a fluorescent screen E. The tube is exhausted. In FIG. 1, C and C indicate cathodes each having a large surface, E indicates a fluorescent screen and A indicates an anode having ten apertures of a shape corresponding to the digits 0 to 9. Arranged between the cathodes C C and the anode is a complex of ten grids which are insulated from one another, each corresponding to one aperture. Grid G corresponds to the aperture having a shape corresponding to the digit 1,

3,082,341 Patented Mar. 19, 1963 grid G corresponds to the aperture having a shape corresponding to the digit 2, etc. Each grid is arranged with respect to the associated apertures so that the potential applied thereto controls he current of the electron beam which can pass through this aperture. Electrical connections (not shown) are present which permit etxernal application of a potential to each grid. In FIG. 1, S and S indicate insulating supports for the first five grids and S and 8., indicate the insulating supports for the other grids. B shows diagrammatically an electron-optical system which may comprise a single electrode of suitable shape to which a given potential is applied.

During operatiOn, the cathodes C and C produce an electron beam, the electrons of which would reach the whole surface of the anode A in the absence of the grids G G etc. If no signal must appear on the screen, the grids have potentials such that not a single electron passes through the anode A. Starting from this condition, it suflices for reproducing the digit 1 to apply the correct potential to the grid G so that this grid allows part of the electron beam to pass through the aperture the shape of which corresponds to the digit 1. The electron-optical system B allows passage of this part of the electron beam and produces a real and enlarged image of the relevant aperture, which fulfills the function of an object, on the screen E.

The tube may be regarded as comprising ten elementary triodes having a common cathode and anode and a fluorescent screen located behind the anode. If all the elementary triodes, except one, are blocked, the beam passing through it strikes the anode. Part of this beam reaches the screen on which a luminous digit appears. During operation, the tube has, for example, nine negative grids and one grid which passes the electrons. Such a tube has a very low consumption, in the order of a millamp., and may be controlled by means of a low voltage, for example between 5 and 10 volts. The input impedances of the grids are high so that the control power is negligible.

FIG. 2 shows another possibility of arranging the various members in an electron tube according to the invention for producing luminous digits. In this figure, members corresponding to FIG. 1 are indicated by the same characters. In the arrangement shown in FIG. 2, the apertures of the anode A are regularly distributed over a circle. The grids are supported by circular insulating supports S and S The operation of the tube shown in FIG. 2 is otherwise similar to that shown in FIG. 1.

On account of its low inertia, this tube is especially suited for devices having a high counting speed. The tube could advantageously be used in a computer having transistor decades. In this application, the tube affords the advantage that the consumption of the counter is not increased to any appreciable extent.

It is not necessary for the character to be reproduced on the fluorescent screen to correspond to a single part of the beam. In another embodiment of the invention, this character may also be obtained by combination of ditferent parts of the beam. For reproducing a sign, it then suflices to apply the proper potential to the grids corresponding to the parts of the beam which must appear on the screen, the other parts of the beam being blocked by the other grids.

FIG. 3 shows an anode having twelve slots formed such that signs approaching the digits 0 to 9 can be composed. By means of potentials applied to the grids associated with these apertures, it is thus possible to reproduce characters corresponding to the digits 0 to 9.

FIG. 4 shows, by way of example, the signs corresponding to the digits 2 and 5. The last-mentioned debut permits a simplification of the focussing member.

It will be evident that the valve may be combined with any device known per se, for example the anode A may have a satisfactory emission of secondary electrons.

What is claimed is:

1. An electron discharge tube for the projection of digits and characters for computers and counters, which comprises an envelope, a cathode for producing a beam of primary electrons, a fluorescent screen, means. arranged between said cathode and said screen for producing a plurality of beams each having a cross-section corresponding to a character, and focussing means for concentrating said character-shaped beams onto the fiuo rescent screen, said means for producing the charactershaped beams being arranged at right angles to the said beam of primary electrons and comprising a conductive anode having perforations corresponding to the characters and a member which controls the electron current, said control member comprising a plurality of grids each positioned to control the electron current passing through one of said anode perforations with a potential applied thereto.

2. An electron discharge tube as claimed in claim 1, in which each anode perforation corresponds to each character and in which the electron current through each perforation is controlled by the potential on the grid associated therewith, the focussing means comprising a magnifying electron-optical system for projecting the character-shaped beams onto a given area of the screen.

3. An electron discharge tube as claimed in claim 1 in which the anode perforations are distributed over a circle, the axis of which coincides with the center line of the discharge tube. A V

4. In a shaped beam tube apparatus wherein an electron beam is generated and projected at one end of the 4 tube toward an electron responsive target at the other end of the tube, including a beam shaping member positioned in the path of the beam for shaping the cross section of the beam into corresponding information symbols the improvement comprising a control conductor network positioned in the path of the generated beam intermediate the one end of the tube and the beam shaping member for controlling the beam so as to permit only a portion of the beam to'project through the beam shaping member forming one selected information symbol at a time.

5. In a shaped beam tube apparatus wherein an electron beam is generated and projected at one end of the tube for impingement upon an electron responsive target at the other end of the tube, the electron beam comprising a plurality of individual electron beams, including a beam shaping member positioned in the path of the beam for shaping the cross section of one of the plurality of individual electron beams into a corresponding information symbol the improvement comprising means positioned in the path of the plurality of individual electron beams intermediate the one end of the tube and the beam shaping member for controlling the beam therethrough so as to permit only one of the plurality of individual electron beams to project therethrough onto the beam shaping member, said beam shaping member forming said one individual electron beam into one selected information symbol at a time.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN ELECTRON DISCHARGE TUBE FOR THE PROJECTION OF DIGITS AND CHARACTERS FOR COMPUTERS AND COUNTERS, WHICH COMPRISES AN ENVELOPE, A CATHODE FOR PRODUCING A BEAM OF PRIMARY ELECTRONS, A FLUORESCENT SCREEN, MEANS ARRANGED BETWEEN SAID CATHODE AND SAID SCREEN FOR PRODUCING A PLURALITY OF BEAMS EACH HAVING A CROSS-SECTION CORRESPONDING TO A CHARACTER, AND FOCUSSING MEANS FOR CONCENTRATING SAID CHARACTER-SHAPED BEAMS ONTO THE FLUORESCENT SCREEN, SAID MEANS FOR PRODUCING THE CHARACTERSHAPED BEAMS BEING ARRANGED AT RIGHT ANGLES TO THE SAID BEAM OF PRIMARY ELECTRONS AND COMPRISING A CONDUCTIVE ANODE HAVING PERFORMATIONS CORRESPONDING TO THE CHARACTERS AND A MEMBER WHICH CONTROLS THE ELECTRON CURRENT, SAID CONTROL MEMBER COMPRISING A PLURALITY OF GRIDS EACH POSITIONED TO CONTROL THE ELECTRON CURRENT PASSING THROUGH ONE OF SAID ANODE PERFORATIONS WITH A POTENTIAL APPLIED THERETO. 